Since we all know by now that air travel takes a giant toll on the earth, maybe you've been resisting those impossibly cheap last-minute weekend getaway deals. Good for you. But what about business travel? For most of us, flying for work falls into the category of "those emissions aren't my fault because my boss made me do it." But a recent study (PDF) by England's Cranfield University found that most companies aren't doing their part in cutting back on flying time. In fact, they're planning even more air miles.

Almost two-thirds of the businesses surveyed (all were UK based) were expecting to increase their air travel budget in the next fiscal year. When lead researcher Keith Mason and his team asked professionals about the reasons for their most recent business trip, 20 percent said it was simply "to get out of the office."

If your company plays fast and loose with the plane tickets, consider pointing out potential travel cuts to your superiors. "A significant amount of travel is for training and in-company meetings," says Mason. "You don't need to press flesh when you are meeting other people that work in your company." Encourage the folks in charge of the office tech budget to invest in high-quality telecommuting software instead of hacking the cheap or free downloads. Take video chat: If there's a delay, or the picture's fuzzy, or you're always losing the connection, your officemates are more likely to get frustrated and quit using the technology. (Only half of the offices in Mason's study were using business-quality videoconferencing software.) If the environmental angle doesn't convince your boss, try mentioning the savings: In the long run, telecommuting will be much cheaper than plane tickets.

If there's really no way around air travel, the single most important thing you can do is to fly economy instead of first class. The Cranfield researchers found that first- and business-class seats are often twice the size of economy seats—which means half the passengers creating the same amount of emissions. Yes, those two giant armrests are much more comfortable than your sleeping seatmate drooling on your shoulder, but the more people crammed onto the plane, the lower the per-passenger emissions. If you're booking your own flights, know that some airlines are greener than others.

Another interesting tidbit: Mason and his colleagues point out that every little bit of weight reduction on flights counts. Though they haven't crunched the numbers, the team speculates that airlines eliminating unnecessary stuff onboard—extra baggage and catering and duty-free shopping trolley—could make a difference in emissions, too. Passengers can help by packing light. And, says one Japanese airline, don't forget to pee before boarding!